Fluoroallylfluorosulfate (FAFS) is today an easily available fluorinated intermediate, which can be prepared in high yield notably via treatment of hexafluoropropylene with sulphur trioxide in the presence of boron-based catalysts, as disclosed in U.S. Pat. No. 4,235,804 (E.I. DUPONT DE NEMOURS) Nov. 25, 1980 and KRESPAN, G., et al. Perfluoroallylfluorosulfate, a reactive new perfluoroallylating agent. J. Am. Chem. Soc. 1981, vol. 103, p. 5598-5599.
This compound has been used with success in a large number of synthetic pathways wherein its reactivity towards nucleophilic agents and its ability to provide by appropriate nucleophilic substitution a perfluoroallyl group is exploited (see e.g. BANKS, Ronald E., et al. Perfluoroallyl fluorosulphonate. Journal of Fluorine Chemistry. 1982, vol. 20, p. 1133-1134).
Among others, mention can be made of synthetic processes involving the reaction of FAFS with polyfluorocarbonyl compounds in the presence of metal fluorides; these latter mentioned are in situ transformed in corresponding polyfluoroalkoxyde compounds which undergo nucleophilic substitution at the fluorosulfate group, yielding corresponding perfluoroallyl-substituted ether compound, as sketched in scheme here below:
Examples of such chemistry can be found in following documents: U.S. Pat. No. 4,292,449 (DU PONT) Sep. 29, 1981; U.S. Pat. No. 4,275,225 (DU PONT) Jun. 23, 1981; U.S. Pat. No. 4,273,728 (DU PONT) Jun. 16, 1981.
On the other side, no effort has been devoted to investigate the addition reactions of FAFS, in particular involving addition on its double bond of fluorine-containing compounds, e.g. hypofluorites, in particular for yielding fluorocarbonyl derivatives.
Actually, hypofluorites are well known to undergo addition reactions towards different olefins either via an electrophilic mechanism (ROZEN, S. Chem. rev. 1996, vol. 96, p. 1717 and ss.) or through a radical route (NAVARRINI, W., et al. Organic perfluoro-hypofluorites: useful reagents in the preparation of fluorinated vinylethers. Recent Res. Devel. Organic Chem. 2004, vol. 8, p. 281-322).
The Applicant has now surprisingly discovered that it is possible to add hypofluorites to the double bond of FAFS without incepting nucleophilic reactions on the fluorosulfate moiety. The FAFS is thus used as suitable synthone for the introduction in the target molecule of C3-saturated oxygenated groups highlighted in scheme herein below:
while preserving fluorosulfate moiety and accessible chemistry thereof, for providing corresponding acyl fluoride derivatives. Actually, reactivity of fluorosulfate groups in these intermediates can be used with success for the manufacture of fluoroacyl compounds, which are indeed interesting precursors for yielding different compounds, like, notably, fluoroethers which can undergo suitable dehydro/halogenation reactions for providing corresponding vinyl ethers.